Fix clipped receipt margins, add time-of-day naming, speed up rotation detection

- vision/document.py: pad_quad() expands the detected quad outward
  before warping so a straight-line contour fit doesn't clip the first
  character of every line on a slightly curled/wrinkled receipt
- ocr/extract.py + llm/vision.py: extract transaction time (HH:MM) so
  same-day repeat visits to a vendor get distinct filenames
  (2023-03-20_1525_walmart.pdf vs. a later same-day trip)
- vision/orient.py: downscale before Tesseract OSD/confidence-sweep
  rotation detection — this was the dominant cost in the detection
  phase (7x speedup: 472s -> 67s on a 36s test video)

tests/test_naming.py

@@ -46,6 +46,27 @@ def test_build_name_nothing_found():
     assert result.source == "none"
 
 
+def test_build_name_with_time_disambiguates_same_day_visits():
+    dt = datetime(2026, 1, 1, 12, 0, 0)
+    morning = build_name("2023-03-20", "WALMART", dt, time="09:05")
+    evening = build_name("2023-03-20", "WALMART", dt, time="18:42")
+    assert morning.stem == "2023-03-20_0905_walmart"
+    assert evening.stem == "2023-03-20_1842_walmart"
+    assert morning.stem != evening.stem
+
+
+def test_build_name_invalid_time_ignored():
+    dt = datetime(2026, 1, 1, 12, 0, 0)
+    result = build_name("2023-03-14", "METRO", dt, time="not-a-time")
+    assert result.stem == "2023-03-14_metro"
+
+
+def test_build_name_time_without_date_ignored():
+    dt = datetime(2026, 1, 1, 12, 0, 0)
+    result = build_name(None, "METRO", dt, time="09:05")
+    assert result.stem == "UNSORTED_metro_20260101_120000"
+
+
 def test_build_name_tax_form_with_year_and_org():
     dt = datetime(2026, 1, 1, 12, 0, 0)
     result = build_name(